The present invention relates to apparatus for controlled movement through an elongated tubular conduit and, more specifically, to apparatus for remotely controlled, stepped movement through a pipe to perform inspections, measurements, and/or other operations within the pipe.
Piping such as that used in nuclear power generating facilities, as well as in other applications, must be inspected prior to use and periodically thereafter to determine whether cracks or flaws are present, e.g., at welded locations, which could indicate an actual or potential hazardous condition. It is desirable that means be provided for transporting inspection apparatus, such as a television camera for performing visual inspections on a remote monitor, through the piping. The transporting apparatus may carry equipment in addition to the camera for assisting in visual or ultrasonic inspection, and/or for performing other operations, such as welding or grinding, within the piping.
Pat. No. 4,615,728 disclosesd apparatus including a carriage mounted on wheels for movement through the interior of elongated piping to assist in visual inspection thereof. Another form of apparatus for movement through linear and curved sections of piping to permit visual inspection and other operations to be performed therein is disclosed in U.S. Pat. No. 4,460,920, of Weber et al. and Japanese Pat. No. 60-85085, of Yemaji. The apparatus of these patents includes two stepping mechanisms having parts moveable into and out of gripping engagement with the inside walls of the piping, and drive means for axial movement of the two mechanisms through the pipe. The stepping mechanisms are connected by further structure including at least one gimbal-type joint to permit articulated relative movement of the two spaced stepping mechanisms. The axial drive means may comprise an extensible and retractable cylinder and piston connected between one of the stepping mechanisms and the structure carrying the gimbal-type joint which, in any event, is necessary in order to permit movement of the apparatus through curved sections of piping.
It is a principal object of the present invention to provide novel and improved apparatus for remotely controlled movement through elongated piping for the purpose of performing visual inspection and/or other operations therein.
A further object is to provide apparatus for stepping-type movement through both linear and curved sections of cylindrical piping with two spaced stepping members having portions movable into and out of engagement with the pipe wall, wherein the stepping members are rigidly connected by an axial drive cylinder, thereby simplifying and economizing the design and manufacture of the apparatus, as well as improving performance and reliability.
Other objects will in part be obvious and will in part appear hereinafter.